Fabric and the treatment of subdivided materials



Mach 25, 1930. s. C. 'SMITH .1,752,210

FABRIC AND THE TREATMENT OF SUBDIVIDED MATERIALS Filed March s1, 1928 4 sneek-sheet 1 /N VENTO@ S. C. SMITH March 25, 1930.

FABRIC AND THE TREATMENT OF SUBDIVIDED MATERIALSl Filed March 51, 1928 4 SheetS-Sheet 2 lll www?

March 2 5, 1930. 5, C, SMITH l 1,752,210

FABRIC AND -THE TREATMENT OF SUBDIVIDED MATERIALS Filed March 31, 1928 4 Sheets-Sheet 3 /NVENTUQ W mw gg March 25, 1930. v s. c. SMITH I 1,752,210

l FABRIC .AND THE TREATMENT vOF SUBDIVIDED MATERIALS `Filed March s1, 1928 4 sheets-sheet 4 5" C. 5km/1% /N YeNTwQ Patentecl'Mar. 25, 1930 i i i I I i UNITED; STATES. PATENT oFI-lcl'azfv FABRIC AND THE TEATMENT OF SUBDVIDED MATERIALS Application led March 31, 1928:, Serial No. 266,437,h and in Great Britain April 5, 1927.

The object of theypresent invention is tox fabric may be formed by using as Warp rubprovide. improved methods and meansl for ber cord preferably of a substantially inexg treating and handling solids or more or less tensible character, that is substantially in-f subdivided materials on filters for solution, extensible under the conditions of Weaving or reaction or both and/or Washing as for inof use in a filter. The weft used is' of a sim- 55 stance in the treatment of ores generally in ilar character and, if desirable, may have a the Wet Way for the separation of the meiexible .and substantially inextensible core, tallic constituents. fer instance a textile core or a metal core It has been found that rubber offers high such as copper or iron Wire in solid or strand- 10 resistance to'erosion such as may be met with ed form as mayY also have the warp'cords. 66 v in filtering of subdivided materials of a hard By using in Warp and/or weft rubberI cord j or gritty nature, for instance in the Wet 0f suitable thickness and strengthv4 and prefscreening of ores as'on shaking or rotating erably cored With,` for instance, copper or 1 screens. Rubber also when suitably comiron Wire it is possible to produce a sufficient pounded resists acid attack and I have found rigidity to enable sameK to maintain a suit- 65 it can even be used in, for instance', rotary able shape independently 'of other means; filters for the treatment of complex sulphide Rubber of suitable quality for'the purpose ores with, for instance, hydrochloric acid, is that having' 10W elasticity or extensibility punder whichconditions the rubber may have or having a reasonable resistance to distorto resist both corrosion due to the acid and tion due for instance to the presence offillers 70 erosion due to suspended gritty particles. or. loading materials. Either lor both the lAll available filtering media, Whether me- Warp and lweft cords may be Similar in aptallic or textile, give Way under such condipearance to rubber-covered copper Wire such tions. Any substantial elastic lstretch in the as that often used for electrical leads and the fabric such as occurs in fabrics hitherto prousual electric "testing Will ensure freedom 75 duced and formed by utilizing with for exfrom iiaws.l ample cotton threads, rubber threads, so -as Strips of the fabric may be made by takto permit stretching of the fabric in one diing a suitable number of vvarps of rubber rectionL should in the present case be avoided. cord of, say, ths to 1/4 of an inch diametery :so In applying my invention to a rotary vacand lacing the weft, which may be of similar 80 uum, suction, or pressure filter, a drum, disc dimensions, continuously from edge to edge or the like of suitable construction may be under suitable tension, beatingrup,` as relined internally or externally with one or quired, to form auniform` fabric. `The Warp more layers of suitably perforate or liquidmay be tensioned and the weft left substan- 115 pervious rubber sheeting material or fabric tia-lly free of tension to Hex and follow-more' 85` Woven from rubber cords which layer or 0r less the contours of the ad]o1n1ng warp layers may be used alone. or for example as sections. fThre Weft may be of rubber cord a protection over one or-more other finerof the'same or substantiallythe same diampore layers say of Wire mesh, cocoanut mateter a the Warp cords' and by any suitable' y 40 ting or asbestosv cloth and rubber material weave a fairly close mesh is obtainable. If 90 l may be used also as a backing for such other; desired for any plurpose a finer or closer mesh layers. The rubber fabricor material whichV is obtained by e sing as Weftand/or Warp may be heldin any convenient mannervwill finer cords than those of the war stand up to erosion of grittymatter under The fabric may be Woven 0 vulcanized treatment and WillA retainE the filtering merubber cord or alternatively ofl unvulcandium in place. It will also guard the filtering ized cord, the Woven fabric being subse- ,f material against `damage such as might arise quently vulcanized afterbeing 'formed to from movement due to changing conditions any desired shape. e

\ of pressure or vacuum. The free ends of the fabric maybe secured A suitable erosion-resisting or protective in any manner and the strip so maintained 100 in shape, for instance, by Vulcanizing or,

if the fabric is to be mounted in flat or curved supports, such mounting, as by means of clamping strips orv the like, may also be depended upon to hold the ends of the fabric cords in position.

The rubber material should preferably offer resistance also to corrosion as by acids and it is found that a suitable rubber for this purpose is heavily loaded material such as the composition bearing the registered trademark Cabtyrit. This materia-l also possesses the desired inextensibility and low elasticity. lVhere a metal core is provided in the Warp and/or weft cords it is desirable to choose such a metal as is inert to the liquors used. f

Referring now to the accompanying drawings Figure l is a fragmentary View of a rubber cord fabric such as may beused in filters according to my invention;

Figure 2fis an elevation partly in longitudinal section of an improved rotary filter drum to show an application of filtering means according to the invention to rotary drum filters in which filtrate liquors are removed by internal pressure;

Figure 3 is an end View of the drum shown in Figure 2, the upper half being shown as a -cross section on the line A-A of Figure 2; Figure 4 is an enlarged fragmentary cross section corresponding to the upper part of Figure 3; i Y i Figure 5 is a similar View to Figure #l but taken at the cent-re of length of the drum;

Figure 6 is a longitudinal section at the same region as Figure 5 A;'

Figure 7 is a fragmentary cross section taken closely adjacent one end of the drum; Figure 8 is an elevation corresponding to Figure 2 of a modifie-d construction of filter drum; ,g

Figure 8a is an enlarged fragmentary longitudinal section'at one corner of the device shown in Figure 8;

Figure 9 is a. half cross section at A-A of Figure 8; v

Figure l() is an enlarged fragmentary cross lsection of the device shown in Figure 8;

Figures 11 and l2 are cross-sectional views corresponding approximately to Figures 5 and 6; f

Figure 13 is a.- diagrammatic elevation showing a plant embodying rotary drums and allied gear. Y l

rl`he apparat-us shown in the drawings is adapted for handling Wet mixtures of a corrosive and gritty nature as for leaching and/ or washing thereof;I for instance it is Well adapted for the treatment of complex oresas described in my prior British Patent specification No. 264,569 and comprises a revoluble steel or like cylinder of any suitable length and diameter which may be supported and rotated 1n any manner, a number-say two tires -a layer of'rubber e preferably vulcanized to the inside of the'shell. On the layer of rubber is superposed a backing of Wooden strips or packing boards f arranged in a cylinder like the staves of a barrel and suitably dowelled as shown or otherwise held securely together. On the inside of this Wooden lining f, between which and the rubber lining referred to a layer of bituminized asbestos cloth or the like may be provided, a composite filter is built. This latter comprises a liquid Venting layer compose-d of longitudinal boards g of Wood such as pitch pine or teak or of any other non-corro'dible material, which are arranged as shown from end to end ofthe drum and for instance radially doWelle-d'to the underlying lining f.

lThe inner surfaces of the boards gare preferably cambered as shown and are grooved or corrugated lengthwise to any suitable depth except at a region near the centre of the length of the cylinder, in which region the grooves arelcut right through the staves as shownfin Figures 5 and 6. The Wooden packing boards f are built so as to leave an annular space 0 behind the perforate regions, of the grooved staves g andopposite to said space and suitable pitched around the drum shell avplurality of outlet branches z/are provided. The remainder of the filter comprises one or more layers of suitably inert fine mesh cloth or the like j held vagainst the grooved Wood surfaces and a protective layer` c of erosionand corrosion-resisting pervious rubber material preferably rubber cord fabric of suitably ne mesh and of the kind described in an earlier part of this specification. These last two layers which may be in any number lof sections for convenience are preferably held on the grooved Wood backing by means of longitudinal strips or slats Z of Wood screwed down preferably by bolts passing through holes m as shown 1n the grooved staves g. The provision of the cambers on ythe groove-d surfaces ensures contact of the filtering layer therewith under suitable circumferential tenslon.

A convenient Way of uniting a number of sheets or the opposite edges of a single sheet of the Woven rubber cord fabric is shown in Figure l wherein ends or edges meeting along a line parallel to the axis of the drum are lapped or butted together and secured conveniently by means of one or' more longitudinal rods or Wires as a linking up by passage strip is turned and entered again in the reverse direction.

At the regions of the filter adjacent t-he drum ends additional transverse wooden strips n as shown in Figure 7 may be provided for holding the endsv of the filtering media in place, the camb`er and grooving preferably being removed or omitted as shown at this region to facilitate the holding of the filter cloth in this manner. Such a construction affords ease of removal of the filter cloths and protective fabric as for replacement or cleaning purposes.

If the erosion-resisting rubber cord'fabric can be made of sufficiently fine mesh for the purpose an underlying finer pore fabric or cloth in some cases need not be used. ln further alternative when desired a composite filter may be employed havingione or more line pore layers as. of glass wool or asbestos cloth and/or a coarser layer of cocoanut matting situate between the pervious rubber lay.- er or fabric and the grooved filter boards or like liquidventing layer. The filter may furh ther comprise two layers of rubber of convenient mesh; for instance the combined layers above referred to may be supported below by a second layer of rubber cord fabric which will act as a backing.

vThe filtrate liquors are removed from the interior of the vessel through the outlet branches h which are in connection with the back or radially outermost side of the lfilter cloth y' by way of the grooves in the staves g and the central annular space o in the wood backing f referred to. rlhe solid residue is removed from the remote end of the drum and provision may be made for continuous or intermittent introduction and withdrawal of liquors.

Agitation of the magma may well be effected upon a lterso constructed without damage thereto and flow of liquor through the filter may be reversed and washing of t e lfilter may be so effected. v

The apparatusldescribed' above is applicable for substantially any process where it is de-v tecting the cloth against the erosive action of the solid material and against mechanical damage. Bychoice of suitable meshor perforation the solids may become keyed against the rubber-and may thus themselves advantageously act as a filter medium.

. If it is desired a rubber cord fabric may be employed having a specialconstruction such as will act to support solids-in 'cake form even in drums of a very large diameter, that iswhere the arching effect is not so great, and even when the solids are of a very granular nature; for instance the fabric may be formed with loops projecting atintervals^from the main surface so as to `improve the keying effect of the solids thereon. A pile fabric may be formed from the rubber cord and employed with similar effects or the latter may `be obtained by other means. An inner layer of cord fabric may be used having if` desired a larger mesh and being held away from the other or outer layer of fabric by any convenient distance and by any means. The solids or cakemay thus form between two layers of the cord fabric and be thus more securely keyed or held in place. lin'eect the fabric when used in a rotary filter drum may have to support that part of the cake above the level of the liquors and to take the strains which otherwise would have to be carried by the filtering material proper which is generally in a very delicate state under the Opf erating conditions. l

The above described apparatus is suitable for carrying out all the required operations of processes of treating ores on the lines of,

my process above referred to by leaching with time stronger than the last, and then washing and finally extracting with brine for removal of the lead chloride without removing the ore or residue from the vessel until finished.

According to one mode ofoperating the ore is first mixed with water in a separate vessel and pumped as a slurry into therotating drum through a non-rotatable axial ltube p passing through a central gland arrangement q rotatable with the end cover 'l'.

When the slurry has been admitted air is introduced as by means of a pipe p4 and pipe p2 through the gland arrangement and the liquors blown out through the filter andthe branches h. The solids are then left as a cake or layer upon thev filter. y Internal pressure is now removed and cocksin connection with the branches L are closed whereupon hydrochloric acid of suitable strength is'pumped into the drum through for instance the tube 'p2 passing through the cover 1'. The rotation of the drum may be stopped or slowed down during the introduction of acid and the reaction of the latter upon the solids may be brought about slowly. to avoid or minimize frothing by gradually rotating thedrum to bring only small @mounts at a time of the cake into the liquor. When all the vcake has been attacked and the violence of the reaction subsides, the drum may then be rotated at a greater speed and the rotation continued for the required time to exhaust or substantially exhaust the acid liquors. Pressure is then applied asbefore and the vcocks connectedV with the branches l1. opened and the weakv acid liquor blown out. The acid treatment is then uns repeated in a similar manner any'number of times but employing successively a stronger acid each time. After removal of the acid liquors the solids are washed by introducing water through-the pipe p2, the internal pressure preferably -being maintained Yso as to keep the solids in cake form onl the rotating filter. The washing may be eected on the countercurrent principle and if necessary this washing may be` followed by one or more Washes with alkali liquors such as weak solutions of lime or soda to neutralize any remaining acid. After removal of the washed liquors as before and release of the internal pressure, a brine solution is pumped into thel vessel through the end cover 'r and a slurry formed with the breaking up of the cake. The brine liquor here acts only as a vehicle whereby the solids are removed from the drum and can be pumped or otherwise led into a separate vessel of the same or a different type for leaching out the lead chloride.

The removal of the ore or slurry is effected.

bymeans of scoops one of which s is shown in the drawings fixed upon the inside of the end cover 1" and'rotatable ywith the drum. The material is thus collected and led tothe centralbranch .t on the end cover through which it may be expelled.

After removal of the solids from the drum the filter .may be washed for reception of a fresh batch. of material by means of a current of Water allowed to flow for any length of.

' time through the filter in either direction,

.35 for instance if desired inwardly through the branches h to the interior of the drum by way of the filter cloth.

The mother liquors remaining after the crystallizing out of the lead chloride from the lbrine liquors may be reutilized for leaching or for forming the slurry in which formthe chloridized ore is removed from the drum.

` In som'e cases the leaching may be effected without removal of the chloridized ore from the drum and in such an event it is preferable ythe solids as a cake throughout all or a number of the various treatments and only thereafter to form a slurry of the solids as for removal, better effects may be'obtained by repulping from time to time and agitating the slurry, reforming the cake duringor at the commencement of each of the various filtering operations. In some cases the cake breaks up on release ofthe lnternal air pressure 1n lthe second to tank T1.

the drum but much depends upon the nature and state of the ore and upon the mesh of the rubber fabric lining. It may be necessary chloridizing liquors may be caused to flow ory circulate continuously into the vessel through the end cover r, through the layer or cake of solid material and out through the branches 5, the strength of said liquors being gradually increased to a maximum concentration and the chloridizing of 'the lead substantially completed in this manner. The concentration of the liquors is then gradually reduced to a minimum concentration as by introduction of acid liquors from previous chloridizing operations whereby to avoid excessive dito blow the solids off the filter for instance by lution of the more concentrated liquorin contactiwith the solid material at thel completion of the chloridizing.

The leaching with brine may be effected in some such manner as has been describedabove.

Referring to the drawing, Figure 13, showing the general layout of a plant suitable for carrying out a process such-as that above indicated for the treatment oflead sulphide ores, in the working of this plant ore and water may be fed into the slurry mixer M1 and pumped by slurry pump P5 to therevolving filter F1; When all the charge is in the filter the watermay be blown out as described and sent to waste by the connection shown.

The ore is then treated with weak hydrochloric acid from tank TlL and when the acid is completely exhausted it is blown otand either sent to waste or treated in another plant for the recovery of any valuable constituents. Stronger' acid treatment from tank T"2 then follows and the resultant liquor is then passed to tankTl. Finally treatment is made with strong hydrochloric acid, this liquor eventually going to tank T2.. f

When the acid treatment is complete the charge is washed acid free. This can be done with small quantities of water so that 'the first wash is strong enough to go to tank T2 and The-other washes can either go to waste or be treated with the other liquors for the' recovery of constituents of value.

The acid treated ore is then discharged as above from the filter into the slurry mixer M2, made into a slurrywith brinegand then pumped by the slurry pump PB into the ro-` ik The lter is then rotated till the hot brine rated solution being then blown out and pumped by pump P7 throughthe cooler C into the classifier D where the lead chloride crystals are recovered while the cold brine returns to tank T4 by pump P2 rlhis treatment with hot brine is repeated till all the lead chloride has'been dissolved out ofthe treated ore. The lead free ore is then washed with water, and the residue discharged fromthe filter. By having two filters in the brine leaching circuit the process can be made continuous as lone lter can be rotated to dissolve the lead chloride while the other is being emptied through the coolers. ln a modification as where weak acid or neutral liquors or slightly alkaline liquors are being used lthe construction of filter andarrangement thereof in the drum and the construction of the latter may be such as is shown in Figures 8 to l2.

The drum shown in section in Figure 8 may be rotatably driven `and supported in.

any manner'and may have a shell d of copper providedr internally, as by riveting, with a number of longitudinally disposed and equally pitched cleat bars u as shown in Figures 88,' 9 and 10 extending from the remote ends of the drum to the central region thereof where 'they butt against the sides of a bridge piece n (see Figures 114 and 12)*providing in its interior an annular passage corresponding to that o referred to in the pre ceding paragraphs. At each of the remote ends of the drum the cleat bars meet with f the inside face of an annular end piece 'v provided for the purpose hereinafter vindicated. C

The grooved backing g for thev filter cloth (and layer or layers of rubber meshgfabric not shown) isprovided in dove-tailed spaces between the adjacent pairs of the cleat bars u being conveniently held in position as by. wedgng or being made a driving fit between the cleat bars and driven from ends into said spaces.

The grooved staves g which may be of any suitable material which-will stand up to the liquors present are shaped as shown in Figure 11 where they butt against the bridge piece fu at the lcentre vof .the drum. The grooves are here cut down through the full depth or thickness ofthe stave g'and the end-thereof is chamfered or undercut-so as to connect the grooves in the staves with the 'interior of the bridge piece through cut-away portions or ports w in the sides of the latter.

' The filter cloth. j', which mayfforI instance be a ne metal gauze, say Monell metal of 400 mesh, and the rubber cord fabric is spread over the grooved Wood 4and the cleat bars and central bridge piece and'is held in place by means of rods fw, w each passing through one of a corresponding number of holes in Modifications 1t 1s the cylinder lrial having finer interstices.'

may be introduced through "the end cover .I

rs if desired by similar means to those previously described with reference to lanother constructionof drum.

To' provide automatic moving of the "treated ore or the like or the residues across theA filter under rotation of the drum, as when it is desired to remove material in a dry state from thedrum, a series of helically arranged guiding members, for instance angle irons y, are provided, these being secured on 'the inside of the protected filter as by bolting through the cloth retainin rods fw,the cleat -barsu and the shell d o the drum. The solids are thus moved towardsthe cover 7'* which is removable axially from the drum end 'when desired. lt Ais preferable to ernn ploy a toggle gear such as is shown for moving the cover from the opened toclosed position. This gear which rotates with the drum can be speedily manipulated as is desirable and can hold the-cover in position with the necessary thrust to prevent leakage during the liquor treatments.

to be understood may be made to the foregoing method4 and constructions`of apparatus or fabrics without departing fromvthe spirit of the invention. Having now described my invention, what ioo` I claim as new and desire to secure by Letters Patent is v 1. In a filter, at least one liquidy venting layer. of perforate rubber material.

2. VIn a filter, at least one liquid venting A layer of woven rubber cord fabric. Y

3. lin a filter,- atleast one liquid venting `layer of perforate rubber material of a re- '5. Ina filter, at least one liquid venting layer of perforate rubber material reinforced by tensile material.

6. ln'a filter, at least one liquid venting layer of fabric woven from cords of rubber resistant to chemical attack and erosion.

' 7. 'ln a lter, at least'one layer of resistant liquid-pervious rubber material laid over to protect another liquid venting layer.

8. In a filter, at least one liquid venting lay- 9. In a filter, at least one liquid venting f layerv of perforate rubber material and at least 4one liquid venting layer of other mate- 10. In a filter, at least one liquid venting layer of perforate rubber materialy and a liquid venting backing of relatively hard material forming a base for said rubber material.`

11. In a'lter, at least one liquid veliting `5 layer of perforate rubber material, at least one liquid venting layer of other material having ner interstices', and a liquid venting backing of relatively hard material formingla base for said rubber materials.

, 12. In a filter according to claim 10, said base-forming hard material constituting a lining for a Wall in a filter vessel. i

13.` In a ilter, at least one liqu1d venting layer of. perforate rubber material of a re-v sistant character, a liquid venting backing of relatively hard material servin as a backing for said rubber material and co stituting an internal lining in a rotary reaction filter.

I4. In a filter, a pluralityof superposed layers of liquidventing material including at least one layer of perforat rubber mate? rial adapted to provide for'keying f solids means against said harder material lbase, said fretaining means comprising clamping elements. u

20. 'In filter apparatus according to claim I9. In filter apparatus according toclaim 16, means for retaining said overlying layer 4.16, said base for said overlying layer means l icomprising 'stave elements in edgewise juxtaposition ,havingy grooved surfaces of cambered configuratlon'andf clamping means Aadapted `for retaining said overlying layer means'l 'against saidcambered surfaces.

21. In. filter apparatus according to claim 17,l said base for saidA overlying layer means comprising stavev elements retained in longi- 'eral wall'of the drum by longitudinally disposed channel elements, said stave elements lhaving longltudinally` grooved surfaces of camberedsection, and means for retaining "tudinal juxtaposition on said inner perrphsaid. overlying layer means against said groovedl surfaces, said retaining means comprising rod elements co-operatmg with said channel elements to clampv said overlying layer means between them.

In testimonywhereof I have signedl my name to this specification.

STANLEY'COCHRAN SMITH.

provide for keying of solids thereupon while l said solids are subjected to liquid treatment.

16. In filtering apparatus, at least onevessel having a lining therein comprising a liquid venting layer o'f hard materlal serving as a base for at least one overlying liquid venting flexible layer including at least one layer l of perforate rubber material 'of a resistant character serving as a protector, means for admitting liquors and solids into said vessel onto said protector layer, and m`eans for removin filtrate liquors from said vessel.

17.' n .reaction -ilter apparatus, atleast I one rotatable drum vessel, a lining on an inner peripheral wall thereof comprising a liquidventing layer of hard material serving 'as a base forat least one overlying liquid venting iexiblev layer including at least one layer i of perforate rjibber material ofI a resistant vcharacter servlng as a rotector, means situated coaxiall of saidwrum adjacent an end region theeo for permitting admission of liquors and solids onto said'protector lay'er l while the druin is rotated,-annular' passage means 1n said drum 1n communication with said liquid venting layers and means in connection with said drum and 4'providing for escape loffiltrate liquors from' said annular passage means.

18. In filter apparatus according to claim 17, means for eifecting removal of solids from said drum, including s'coop'means adapted to lead said s olidsto an'outlet disposed in. an end ofusaid drum remote from said admiss1on measn.

'ion 

